The studies with a normal adrenal cell have demonstrated the unique functions of cyclic AMP and cyclic GMP in the regulation of steroidogenesis. These studies, when repeated in the adrenocortical carcinoma cell, show various metabolic defects which are related to the modified cyclic nucleotide metabolism. These defects are very specific to various components of cyclic AMP and cyclic GMP metabolic systems. The proposed project is designed to continue and extend these studies to appreciate fully the details of the molecular events in the ACTH-stimulated steroidogenesis in a normal cell, and then to utilize this knowledge to study the abnormalities in the malignant cell. Ultimately, we expect our findings to provide a better understanding of the mechanisms of the autonomous hormonal control in the endocrine neoplasia. In the planned research the methodology used involves the purification of cyclic nucleotide dependent protein kinase enzymes, and the study of these systems by radioactive tracer techniques.